A need has existed for an inexpensive constant depth mechanism that can be scaled up or down in size to provide accurate depth-control for incorporating into fishing lures as well as other uses such as scalable multi-purpose carriers for mounting and carrying sensing and measurement devices for underwater operations photography, pH measurements, radiation monitoring, sound monitoring, temperature mapping, pollution mapping, or sea floor mapping while being retrieved, towed, trolled, or otherwise pulled.
With regard to fishing, in previous years the major fishing lures or plugs considered deep divers were oversized versions of the plugs that you would use in cast fishing. There was a slight problem with the concept. While a larger sized Hellbender, Bomber Waterdog, or MudBug (common brand names of diving lures) would reach deeper haunts when trolled, the same did not apply when casting the plugs. It was difficult to consistently get out the same amount of line on a cast and secondly it was problematic to maintain anywhere near the same speed of retrieval from cast to cast when compared to the consistent speeds one can achieve with trolling. The result of trying to accomplish this was that the best reels would prematurely wear out over time.
In approximately the last 10 years there have been an ever-increasing number of true deep diving baits. These have been developed through the application of elongated lips on plastic molded lugs, which in some cases have also been modified by having a slight bend at the end of the lip. This bend enhances the dive of the plug in the water by giving it a steeper dive angle upon retrieve. To a certain degree this concept might work on any plug that dives on retrieve. Some have actually altered the dive angle by adding weight to the front of the plug, thus customizing it. This was a difficult to accomplish without changing the tracking of the plug on retrieve. Alternately, the dive angle was increased by adding an over-sized treble in the front hook position to shift the center of mass forward. Unfortunately because of the larger hook, the lure will be less weedless.
Most deep diving plugs have a couple of things in common. The lip will be proportionally larger in ratio to the body size and the other feature is that many of these, when viewed from the front or back, will have a narrow body contour from side to side. The lip obviously aids in the dive, but its effect would be useless if the body wasn't able to cut through the water with less resistance. Another common characteristic of diving plugs is that plugs with wider wobbles on retrieve are less likely to go as deep on the same speed of retrieve as a comparable size plug which has a less pronounced wobble.
The depth to which a lure is supposed to dive has always been a subject to more variables or factors than the retrieval speed and dive angle of the lip. There has been a primary additional factor attributable to the size of line used in the company test. In the real world you weren't going to cast a 20-foot rated plug on six-pound test very many times due to the stress on the small diameter line and even fewer if you were in any place where there was underwater structure.
Regarding structure, many of the deep divers are going to be less prone to becoming entangled in underwater vegetation or structures. The reason for this is the same sharp diving angle is going to keep the hooks protected during retrieval by the body and the lip of the plug. If you simply release pressure upon feeling resistance, the plug will often float back off the hang-up.
If you are going to fish deep diving cranks it was advisable to use nothing less than a 6½-foot rod. When using the larger and deepest diving plugs it was advisable to actually go to a 7- or even a 7½-foot rod. These longer rods provide a maximum distance cast, and also reduce much of the shock from the lure pressure during retrieval (which isn't a bad concept since the other option would increase fatigue to the fisherman).
The gears have been reinforced on most quality reels so that you can get a good life expectancy even if you throw a lot of deep cranks. The higher ratio gear reels are preferable for the same reason to use a stiffer rod, to control slack and move the fish when needed.
Some who would fish with deep cranks do not like the effort of “driving” or reeling a lure to maximum diving depth. Well it doesn't have to float to be a deep crankbait. In fact those with count-down potential are also excellent deep cranks. About 95 percent of fishermen do not work swimming type baits such as Rat-L-Traps by letting them sink to the deeper water. Plugs such as these are only as effective as the fishermen's knowledge of the depth to which they let it sink. If a fishermen want to use deep crank lures to establish a reproducible pattern they must “count it down.” While you have less control over the constant depth of a diver-type of crank you can much more easily control the depth on retrieve of a Trap or Hot Spot.
A common concern for fishermen using a crankbait lure is that they are going to hang up on underwater debris or vegetation due to the inability to maintain depth. As a consequence of being unable to maintain depth, lures are going to hang up, so it has been wise to use sufficiently heavy line to feel comfortable that they can get the lures loose. Due to the hang-up potential, fishermen are advised to invest in buying a lure retriever. Most tackle shops have various versions or they can be built from a saltwater lead and a couple of dog collar drop-chains dangling from the lead.
An alternate means for controlling constant bait depth is a downrigger. The downrigger is a winch-type mechanism that feeds cable off a rotating reel through a guide system along an extension arm. A weight is attached to the end of the cable and the line release is attached to the weight. The fishing line from an independent rod and reel is attached to the release mechanism on the downrigger cable. By lowering the weight (ball), you can drop the line down to the desired depth. A footage counter is connected to the reel unit to indicate the specific amount of cable that has been released. At the desired depth the reel is locked into place.
Downrigger models range from portable clamp on styles, permanent mounts, some with electronic motor retrieval systems capable of lifting downrigger weights of up to 10 lbs 100 feet down by a simple push of a button. Other new features on downriggers are networked with electronics, a speed sensor can be attached to the cable indicating how fast the lure is moving at that depth. Bottom tracking sonar systems using a transducer on the transom sends a programmed signal to the downrigger that will raise and lower automatically the weight off the bottom, or jig the weight up and down giving action to the lure with an auto setting. Multiple downriggers can be operated off of the same sonar signal working simultaneously.
Lead Core (Weighted Trolling Line) came on to the fishing scene during the 1970's as weighted trolling line. This allowed Salmon, Lake Trout, Steelhead and Walleye anglers the ability to use certain types of lures to reach depths were the fish are present. Lead Core is constructed of two components, the inner wire made of soft pliable lead and the outer sheath of nylon braid which is color coated every ten yards for metering purposes, referred to as the term colors. Recently a new environmentally safe non lead line was introduced using a metal alloy wire in lieu of lead. Weighted trolling lines are available in 100-200 yard spools ranging from 12 lb to 45 lb. test ratings.
The amount of weighted trolling line spooled on your reel is totally dependent on the species of fish you are targeting by the depth required. An example of this method can be observed on the Great Lakes where walleye anglers may use 30 yards of weighted line or three colors whereas a Salmon angler may spool the entire 200 yards or twenty colors. The approximate rule dependent on the pound-test is every two yards of weighted line will sink one foot. The only reel type to be used for weighted trolling line is a conventional level wind-trolling reel and the line capacity is based on the species (smaller for walleyes larger for salmon). In spooling the reel, a line backing should always be used as this helps to fill the reel to the proper line amount. The most popular line backing used today is the super braid which is tied to the weighted line using an Albright knot, after the weighted line is spooled, a monofilament/fluorocarbon leader is tied using a Uni-knot. (Note: When tying backing a leader to lead core, remove the inner wire) This entire line set-up is referred as “segmented” which when properly used places the weighted line and lure at the feeding depth of fish. Trolling weighted (lead core) line is a technical process requiring a high level of expertise and knowledge. If considering using this trolling technique, success would be best served if you research the fishery and species before purchasing the proper equipment.
Wire line is another trolling line option especially if fishing requires lures to go very deep. Wire lines come in a variety of choices, solid and stranded. Solid wire known as Monel is a metal-nickel-copper alloy, which will go deeper than stranded line based on the ultra-thin line diameter and weight. Stranded offers many versions made of stainless steel or copper, in cable-laid wire, 49 strand, three and seven strand wire some of these come with vinyl coatings used mainly as leader material.
Snap weights are an attached/removable weight system ideal in getting your bait down to suspended Walleyes, Salmon, Trout, Bass and Muskies when flat line trolling. The weight sizes are relatively heavy ½ to 8 oz. that snaps on to the fishing line by a spring tension clamp, the weight is secured on a metal ring below. Upon a fish strike the line is retrieved to the snap weight and unclipped from the line to fight the fish. With the various sizes of weights available, this method offers a range of different depth settings without having to re-rig the rod. Most anglers start by using the 50/50 system placing the snap weight halfway out on the line. Moving the snap weight closer to the lure increases the response to the movements of the boat and the rod while moving the weight farther away from the lure it becomes less responsive, but more influenced by the action of wind and waves. The farther back the snap weight is from the lure will reduce spooking the fish from biting. Snap weights can be used on braided line, low stretch monofilament/fluorocarbon and lead core line.
The present state of the art regarding a device, for example a lure, that will seek to achieve a constant depth while traveling through a body of water includes, but is not limited to, fishermen attempting to retrieve a lure via previously mentioned traditional methods, and/or troll a fishing lure that will seek and ultimately maintain a constant depth in the water. The purpose of attempting to target or acquire a specific depth in water while fishing (without special materials such as weighted or color coded line or weight snaps) is a typical desire of most fishermen due to the stratified depth behavior of fish.
Traditional crankbait lures are a type of fishing lure that, by virtue of an angled bill on the forward-most portion of the lure, succumb to a tendency to dive once pulled forward through the water either by retrieval from a stationary fisherman retrieving his cast or from a fisherman trolling the lure behind a fishing vessel. These lures are classified by depth which is a function of bill surface area, bill angle, rate of retrieval, weight of fishing line and angle of fishing line. These depth classifications apply to two main camps of fishing technique: Cast fishing (from shore, boat, dock, etc.) and trolling (from a boat in motion). For most cast fishing scenarios a crankbait lure assumes a general parabolic curve where the first portion of the retrieval is dedicated to the diving action of the lure. At some critical point (specific to each individual lure) the vertical forces of the fishing line overpower the diving forces of the bill and the lure begins its return to the surface. This method of retrieval requires much skill and technique on the fisherman and allows for a large margin of error when trying to target a specific depth. Conversely, in trolling there is well known and published data outlining specifics of the variables involved in accurately presenting your lure at its target or desired depth. These models, or dive curves, consider two major variables: trolling speed and amount of fishing line between the lure and the reel. As long as these two variables are known, the targeted trolling depth can be achieved with relative accuracy but the two variables must be held constant to achieve the desired depth.
Present methods using current products for depth-specific-fishing, while in motion, and require considerable amounts of skills and special materials as related to the retrieval/trolling speed of the lure and scope of the fishing line. Scope of the fishing line refers to the length of fishing line from the fisherman to the device and makes maintaining a constant depth at various retrieving or trolling speeds problematic without a constant depth mechanism.
A constant or automatic depth-control device is a device equipped with an automatic or constant depth-controlling mechanism. Many other applications other than fishing for constant depth devices are possible using special or general purpose carriers with constant depth mechanisms incorporated along with sensing and measurement devices for underwater operations including photography, pH measurements, radiation monitoring, sound monitoring, temperature mapping, pollution mapping, or sea floor mapping while being retrieved, towed, trolled, or otherwise pulled.
Based on the aforementioned needs and problems, there is a necessity for automatic depth-control mechanisms, devices, systems, and methods capable of achieving and then maintaining a constant depth while traveling through the water at various speeds. All this without special materials and requiring minimal skill on the part of the users to achieve and maintain a constant depth while performing an underwater task such as fishing, photography, sampling, mapping or data collection.
A dynamic dive plane, as applied to an automatic depth-control device (“dynamic lure”) includes various end effector shapes or dynamic extensions such as a lip, bill, or fin design revolutionizes the various constituents of typical crankbait lure fishing techniques by eliminating many of the aforementioned variables.
In cast-fishing applications the dynamic lure will “seek” and “acquire” its target depth, but will maintain this target depth upon reaching it despite most techniques employed by the fisherman. In trolling applications, the two variables that define typical dive curves (speed and length of line) are eliminated by allowing the fisherman to travel at any reasonable trolling speed with any amount of line (above a certain critical length) and achieve the target depth.
The exact mechanisms and some of the various embodiments outlining these and other depth-control accomplishments follow, but the general concept is that by allowing the dynamic dive plane; lip, bill, or fin of this lure to dynamically react to pressure changes in the water column or depth, the lure will improve the accuracy of achieving and maintaining target depth and increase the lure's presentation time at target depth or in an alternative broader sense, the time at target depth for a multi-purpose carrier to perform a variety of tasks including sensing (such as for pH levels and O2, or pollutant concentrations), photography, bottom depth mapping, fish attraction, and temperature mapping.